Details of the Researcher

PHOTO

Daisuke Shiga
Section
Institute of Multidisciplinary Research for Advanced Materials
Job title
Assistant Professor
Degree

  • 博士（理学）（東北大学）

  • 修士（理学）（東北大学）

e-Rad No.
00909103
Researcher ID
GVU-7893-2022
Profile

Dr. Daisuke Shiga completed his Ph.D. in Science from Tohoku University, Japan, in March 2021 and has been an Assistant Professor of Physical Chemistry at the Institute of Multidisciplinary Research for Advanced Materials (IMRMA), Tohoku University, since April 2021. He is also an Associate Researcher at the Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), Japan, working predominantly on the synthesis and synchrotron analysis of functional oxide nanostructures.

無機材料研究部門 ナノ機能物性化学研究分野　〒980-8577 仙台市青葉区片平2-1-1

Research History 2

  • 2022/04 - Present
    Tohoku University　Faculty of Science

  • 2021/04 - Present
    Tohoku University　Institute of Multidisciplinary Research for Advanced Materials

Education 5

  • Tohoku University　Graduate School of Science　Department of Chemistry

    2018/04 - 2021/03

  • Tohoku University　Graduate School of Science　Department of Physics

    2016/04 - 2018/03

  • University of Hyogo　School of Science　Department of Material Science

    2012/04 - 2016/03

  • 福島県立相馬高等学校　(理数科), 卒業

    2011/04 - 2012/03

  • 福島県立原町高等学校　(普通科), 転学

    2009/04 - 2011/03

Committee Memberships 1

  • 東北大多元研 多友会　幹事

    2023 - 2025

Professional Memberships 3

  • Japan Society of Applied Physics (JSAP)

    2017/10 - Present

  • Japanese Society for Synchrotron Radiation Research (JSSRR)

    2017/10 - Present

  • Physical Society of Japan (JPS)

    2016/10 - Present

Research Interests 3

  • Oxide Nanostructures

  • Strongly Correlated Systems

  • Synchrotron-Radiation Spectroscopies

Research Areas 1

  • Nanotechnology/Materials / Thin-film surfaces and interfaces / Oxide electronics

Awards 8

  1. 多元物質科学研究奨励賞（東北大 籏野奨学基金）

    2025/09

  2. 論文賞（JSAP 薄膜・表面物理分科会）

    2022/03

  3. 振興会賞（東北大 青葉理学振興会）

    2021/03

  4. 化学専攻賞（東北大院理）

    2021/03

  5. 学生奨励賞（量子ビームサイエンスフェスタ）

    2021/03

  6. 学生発表賞（日本放射光学会年会・放射光科学合同シンポジウム）

    2021/01

  7. Editors' Suggestion (PRB)

    2020/09

  8. 多元物質科学奨励賞（東北大 科学計測振興基金）

    2019/12

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Papers 30

  1. Interface-induced collective phase transition in VO2-based bilayers studied by layer-selective spectroscopy

    D. Shiga, S. Inoue, T. Kanda, N. Hasegawa, M. Kitamura, K. Horiba, K. Yoshimatsu, A. F. Santander-Syro, H. Kumigashira

    arXiv:2505.20448　2025/05/26

  2. Common anion rule in oxide heterointerfaces: Experimental verification by in situ photoemission spectroscopy International-journal Peer-reviewed

    R. Hayasaka, T. Kanda, Y. Masutake, D. K. Nguyen, N. Hasegawa, S. Inoue, A. Wada, M. Kitamura, D. Shiga, K. Yoshimatsu, H. Kumigashira

    APL Mater.　12　071111　2024/07/15

    Publisher: AIP Publishing

    DOI： 10.1063/5.0223269 　

    eISSN： 2166-532X

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    The band alignment at the interface is one of the fundamental parameters for designing electronic devices and artificial functional materials. However, there is no firmly established guideline for oxide heterostructures, limiting the functional design of oxide heterostructures. Here, we provide spectral evidence that the band diagram of oxide heterointerfaces is well described by the Zhong and Hansmann scheme based on the common anion rule [Z. Zhong and P. Hansmann, Phys. Rev. X 7, 011023 (2017)]. By utilizing the elemental selectivity of Ti 2p–3d resonant photoemission for the Ti 3d state near the Fermi level, we directly visualize the presence or absence of charge transfer from the overlayer films to SrTiO3 in prototypical heterointerfaces of SrVO3/SrTiO3 and SrNbO3/SrTiO3. It is found that the charge transfer occurs in SrNbO3/SrTiO3 but not in SrVO3/SrTiO3, as predicted by the Zhong and Hansmann scheme, indicating that the presence or absence, as well as the sign and amount, of interfacial charge transfer is predicted by this scheme. Our findings provide guidelines for designing and controlling the functionalities in oxide nanostructures.

  3. Electronic phase diagram of Cr-doped VO2 epitaxial films studied by in situ photoemission spectroscopy International-journal Peer-reviewed

    D. Shiga, X. Cheng, T. T. Kim, T. Kanda, N. Hasegawa, M. Kitamura, K. Yoshimatsu, H. Kumigashira

    Phys. Rev. B　108　045112　2023/07/11

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.108.045112 　

    ISSN： 2469-9950

    eISSN： 2469-9969

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    Through in situ photoemission spectroscopy (PES), we investigated the changes in the electronic structure of Cr-doped VO2 films coherently grown on TiO2 (001) substrates. The electronic phase diagram of CrxV1−xO2 is drawn by a combination of electric and spectroscopic measurements. The phase diagram is similar to that of bulk CrxV1−xO2, while the temperature of metal-insulator transition(TMIT) is significantly suppressed by the epitaxial strain effect. In the range x = 0−0.04, where TMIT remains unchanged as a function of x, the PES spectra show a dramatic change across TMIT, demonstrating the characteristic spectral changes associated with the Peierls phenomenon. In contrast, for x > 0.04, the TMIT linearly increases, and the metal-insulator transition (MIT) may disappear at x = 0.08−0.12. The PES spectra at x = 0.08 exhibit pseudogap behavior near the Fermi level, whereas the characteristic temperature-induced change remains almost intact, suggesting the existence of local V-V dimerization. The suppression of V-V dimerization with increasing x was confirmed by polarization-dependent x-ray absorption spectroscopy. These spectroscopic investigations reveal that the energy gap and V 3d states are essentially unchanged with 0 ≤ x ≤ 0.08 despite the suppression of V-V dimerization. The invariance of the energy gap with respect to x suggests that the MIT in CrxV1−xO2 arises primarily from the strong electron correlations, namely, the Peierls-assisted Mott transition. Meanwhile, the pseudogap at x = 0.08 eventually evolves to a full gap (Mott gap) at x = 0.12, which is consistent with the disappearance of the temperature-dependent MIT in the electronic phase diagram. These results demonstrate that a Mott insulating phase without V-V dimerization is stabilized at x > 0.08 as a result of the superiority of Mott instability over the Peierls one.

  4. Quantization condition of strongly correlated electrons in oxide nanostructures Peer-reviewed

    T. Kanda, D. Shiga, A. Wada, R. Hayasaka, Y. Masutake, N. Hasegawa, M. Kitamura, K. Yoshimatsu, H. Kumigashira

    Commun. Mater.　4　27　2023/04/25

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s43246-023-00354-7 　

    eISSN： 2662-4443

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    Abstract Some oxide nanostructures have recently been shown to host quantum well (QW) states that are promising for quantum device applications by designing the wave function of their strongly correlated electrons. However, it is unclear why QW states only appear in certain oxides, limiting the possibilities of wave-function engineering. Here, we demonstrate that the electron mean free path λ is one of the essential conditions to form standing waves of strongly correlated electrons in oxide nanostructures. We have investigated the QW states formed in SrTi1–xVxO3 (STVO) ultrathin films using in situ angle-resolved photoemission spectroscopy. The controllability of λ in STVO while maintaining an atomically flat surface and chemically abrupt interface enables us to examine the evolution of QW states with varying λ. A detailed analysis reveals that the intensity of the QW states is almost linearly correlated to λ and may disappear at the Ioffe–Regel criterion, corresponding to the nearest neighbor inter-vanadium distance in STVO. Our findings provide design guidelines for creating and controlling novel quantum phenomena in oxide nanostructures.

  5. Electronic band structure of Ti2O3 thin films studied by angle-resolved photoemission spectroscopy Peer-reviewed

    N. Hasegawa, K. Yoshimatsu, D. Shiga, T. Kanda, S. Miyazaki, M. Kitamura, K. Horiba, H. Kumigashira

    Phys. Rev. B　105　235137　2022/06/27

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.105.235137 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  6. Resonant tunneling driven metal-insulator transition in double quantum-well structures of strongly correlated oxide International-journal Peer-reviewed

    R. Yukawa†, M. Kobayashi†, T. Kanda†, D. Shiga†, K. Yoshimatsu, S. Ishibashi, M. Minohara, M. Kitamura, K. Horiba, A. F. Santander-Syro, H. Kumigashira

    Nat. Commun.　12　7070　2021/12/03

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41467-021-27327-z 　

    eISSN： 2041-1723

  7. Electronic structure of SrTi1−xVxO3 films studied by in situ photoemission spectroscopy: Screening for a transparent electrode material Peer-reviewed

    T. Kanda, D. Shiga, R. Yukawa, N. Hasegawa, D. K. Nguyen, X. Cheng, R. Tokunaga, M. Kitamura, K. Horiba, K. Yoshimatsu, H. Kumigashira

    Phys. Rev. B　104　115121　2021/09/10

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.104.115121 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  8. Thickness dependence of electronic structures in VO2 ultrathin films: Suppression of the cooperative Mott-Peierls transition International-journal Peer-reviewed

    D. Shiga, B. E. Yang, N. Hasegawa, T. Kanda, R. Tokunaga, K. Yoshimatsu, R. Yukawa, M. Kitamura, K. Horiba, H. Kumigashira

    Phys. Rev. B　102　115114　2020/09/09

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.102.115114 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  9. Emergence of metallic monoclinic states of VO2 films induced by K deposition International-journal Peer-reviewed

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, K. Horiba, H. Kumigashira

    Phys. Rev. B　99　125120　2019/03/14

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.99.125120 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  10. Mott insulating state of IrO6 honeycomb monolayer structured in ilmenite-type oxide superlattice International-journal Peer-reviewed

    M. Negishi, K. Fujiwara, S.-H. Jang, Y.-F. Zhao, S. Sasano, R. Ishikawa, N. Shibata, D. Shiga, H. Kumigashira, Y. Nakamura, H. Kishida, Y. Motome, A. Tsukazaki

    Phys. Rev. Mater.　9　086202　2025/08/12

    Publisher: American Physical Society (APS)

    DOI： 10.1103/gz4v-8mds 　

    eISSN： 2475-9953

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    Quantum magnetism based on the Kitaev honeycomb model has been intensively studied both by theoretical material design and experimental materialization. In contrast to the considerable progress of theoretical modeling and experiments on bulk crystals, it is still difficult to find a candidate material applicable to thin films and devices toward future quantum computation. Here we clearly demonstrate a Mott insulating state of IrO6 honeycomb monolayer structured in ilmenite-type Mg−Ir−O/MgTiO3 superlattices, which is a good candidate of the Kitaev honeycomb magnet applicable to devices. Electronic states detected by photoelectron spectroscopy agree well with those in theoretical band calculations. The stabilized superlattice with the Mott gap state is a promising platform to examine the device physics of the Majorana fermions and the Z2 fluxes in the Kitaev honeycomb model, suggesting the thin-film techniques are quite beneficial for triggering the exploration of quantum computation in designable and evolvable heterostructures.

  11. Out-of-phase plasmon excitations in the trilayer cuprate Bi2⁢Sr2⁢Ca2⁢Cu3⁢O10+𝛿 International-journal Peer-reviewed

    S. Nakata, M. Bejas, J. Okamoto, K. Yamamoto, D. Shiga, R. Takahashi, H. Y. Huang, H. Kumigashira, H. Wadati, J. Miyawaki, S. Ishida, H. Eisaki, A. Fujimori, A. Greco, H. Yamase, D. J. Huang, H. Suzuki

    Phys. Rev. B　111　165141　2025/04/21

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.111.165141 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  12. Large Seebeck coefficient driven by “pudding mold” flat band in hole-doped CuRhO2 International-journal International-coauthorship Peer-reviewed

    A. J. Thakur, M. Thees, F. Fortuna, E. Frantzeskakis, D. Shiga, H. Kuriyama, M. Nohara, H. Takagi, H. Kumigashira, A. F. Santander-Syro

    Phys. Rev. Mater.　9　L032401　2025/03/24

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevmaterials.9.l032401 　

    eISSN： 2475-9953

  13. High surface electron-proton mixed conduction at medium temperature of c-axis oriented BaCe0.7Ru0.1Y0.2O3-δ thin film International-journal Peer-reviewed

    N. Kaneda, G. Notake, Y. Wang, R. Kaneko, R. Tabuchi, R. Morizane, D. Shiga, H. Kumigashira, T. Higuchi

    Jpn. J. Appl. Phys.　64　02SP30　2025/02/24

    Publisher: IOP Publishing

    DOI： 10.35848/1347-4065/adb297 　

    ISSN： 0021-4922

    eISSN： 1347-4065

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    Abstract To realize practical anode electrode film for solid oxide fuel cells (SOFCs) operating at a medium temperature range, we have prepared c-axis oriented BaCe0.7Ru0.1Y0.2O3-d (BCRY) thin films on an MgO (100) substrate by RF magnetron sputtering. The oxygen vacancies concentration was quantitatively evaluated by X-ray absorption spectroscopy and defect chemical analysis. Proton conductivity was proven from the O 1s photoemission spectrum showing an OH- peak formed on the oxygen ion sites. Electron conductivity was proven from small density-of-state at the Fermi level (EF) and the energy difference between the top of the valence band and the EF, which is close to the activation energy of the conductivity. The wet-annealed BCRY thin film, which exhibit surface electron-proton mixed conductivity of more than 10-3 S/cm at 300 °C, can be applied as a practical anode electrode film with high chemical reaction for SOFC operating in the medium temperature range.

  14. Resistive control of b-axis oriented VO2 thin film by lithium ions diffusion from LiCoO2 buffer layer International-journal Peer-reviewed

    R. Kaneko, T. Yamada, R. Morizane, N. Kaneda, R. Tabuchi, G. Notake, D. Shiga, H. Kumigashira, T. Higuchi

    Jpn. J. Appl. Phys.　64　02SP28　2025/02/18

    Publisher: IOP Publishing

    DOI： 10.35848/1347-4065/adaf1e 　

    ISSN： 0021-4922

    eISSN： 1347-4065

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    Abstract Vanadium dioxide VO2 thin films can be applied as electrolyte of electric double layer transistor or positive electrode for all-solid-state lithium-ions batteries. In order to verify the charge behavior between the Li+ ion conductor LiCoO2 and VO2, we have investigated the electrical conductivity and electronic structure of b-axis oriented VO2/LiCoO2 multilayer film prepared on Al2O3 (0001) substrates by RF magnetron sputtering. The amount of excess oxygen in the VO2/LiCoO2 multilayer film was evaluated to be ~22.5% by X-ray photoemission spectroscopy. The electrical resistivity of the multilayer film increases with temperature from 290 to 330K, and decreases reversibly above 330K, indicating the Li+ ion conduction. The electron correlation energy of the VO2/LiCoO2 multilayer and VO2 thin film are ~3.4 eV and ~2.4 eV, respectively. These results indicate that the carrier number of the VO2 thin film can control by diffusion of Li+ ions from LiCoO2 buffer layer.

  15. Rocksalt-type heavy rare earth monoxides TbO, DyO, and ErO exhibiting metallic electronic states and ferromagnetism International-journal Peer-reviewed

    S. Sasaki, D. Oka, D. Shiga, R. Takahashi, S. Nakata, K. Harata, Y. Yamasaki, M. Kitamura, H. Nakao, H. Wadati, H. Kumigashira, T. Fukumura

    Dalton Trans.　54　1521　2025/01/28

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/d4dt03214d 　

    ISSN： 1477-9226

    eISSN： 1477-9234

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    Rocksalt-type heavy rare earth monoxides REOs (RE = Tb, Dy, Er) were synthesized as single phase epitaxial thin films for the first time. They exhibited metallic electronic states and a much higher TC than the corresponding rare earth nitrides.

  16. Surface terminations control charge transfer from bulk to surface states in topological insulators International-journal Peer-reviewed

    K. Fukumoto, S. Lee, S. Adachi, Y. Suzuki, K. Kusakabe, R. Yamamoto, M. Kitatani, K. Ishida, Y. Nakagawa, M. Merkel, D. Shiga, H. Kumigashira

    Sci. Rep.　14　10537　2024/05/08

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41598-024-61172-6 　

    eISSN： 2045-2322

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    Abstract Topological insulators (TI) hold significant potential for various electronic and optoelectronic devices that rely on the Dirac surface state (DSS), including spintronic and thermoelectric devices, as well as terahertz detectors. The behavior of electrons within the DSS plays a pivotal role in the performance of such devices. It is expected that DSS appear on a surface of three dimensional(3D) TI by mechanical exfoliation. However, it is not always the case that the surface terminating atomic configuration and corresponding band structures are homogeneous. In order to investigate the impact of surface terminating atomic configurations on electron dynamics, we meticulously examined the electron dynamics at the exfoliated surface of a crystalline 3D TI (Bi$$_2$$Se$$_3$$) with time, space, and energy resolutions. Based on our comprehensive band structure calculations, we found that on one of the Se-terminated surfaces, DSS is located within the bulk band gap, with no other surface states manifesting within this region. On this particular surface, photoexcited electrons within the conduction band effectively relax towards DSS and tend to linger at the Dirac point for extended periods of time. It is worth emphasizing that these distinct characteristics of DSS are exclusively observed on this particular surface.

  17. Electronic Properties of Chiral IrGe4 Studied by Angle Resolved Photoemission Spectroscopy and Band Structure Calculation International-journal Peer-reviewed

    G. Hayashi, T. Shimaiwa, M. Okawa, N. Nakamura, R. Higashinaka, T. D. Matsuda, Y. Aoki, M. Kitamura, D. Shiga, H. Kumigashira, M. Kopciuszynski, A. Barinov, N. L. Saini, T. Mizokawa

    J. Phys. Soc. Jpn.　93　014702　2024/01/12

    Publisher: Physical Society of Japan

    DOI： 10.7566/jpsj.93.014702 　

    ISSN： 0031-9015

    eISSN： 1347-4073

  18. Large Perpendicular Magnetic Anisotropy Induced by an Intersite Charge Transfer in Strained EuVO2H Films International-journal Peer-reviewed

    M. Namba, H. Takatsu, R. Mikita, Y. Sijia, K. Murayama, H.-B. Li, R. Terada, C. Tassel, H. Ubukata, M. Ochi, R. Saez-Puche, E. P. Latasa, N. Ishimatsu, D. Shiga, H. Kumigashira, K. Kinjo, S. Kitagawa, K. Ishida, T. Terashima, K. Fujita, T. Mashiko, K. Yanagisawa, K. Kimoto, H. Kageyama

    J. Am. Chem. Soc.　145　21807　2023/09/28

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/jacs.3c04521 　

    ISSN： 0002-7863

    eISSN： 1520-5126

  19. Thickness-dependent magnetotransport properties of rocksalt NdO epitaxial thin films: observation of a ferromagnetic phase far above the Curie temperature International-journal Peer-reviewed

    D. Saito, D. Oka, K. Kaminaga, M. Kitamura, D. Shiga, H. Kumigashira, T. Fukumura

    J. Mater. Chem. C　11　12400　2023/08/22

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/d3tc02478d 　

    ISSN： 2050-7526

    eISSN： 2050-7534

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    A weak ferromagnetic phase was observed far above the TC in NdO thin film.

  20. Electronic structure reconstruction by trimer formation in CsW2O6 studied by x-ray photoelectron spectroscopy International-journal Peer-reviewed

    R. Nakamura, D. Takegami, A. Melendez-Sans, L. H. Tjeng, M. Okawa, T. Miyoshino, N. L. Saini, M. Kitamura, D. Shiga, H. Kumigashira, M. Yoshimura, K.-D. Tsuei, Y. Okamoto, T. Mizokawa

    Phys. Rev. B　106　195104　2022/11/02

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.106.195104 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  21. Rocksalt CeO epitaxial thin film as a heavy-fermion system transiting from p-type metal to partially compensated n-type metal by 4f delocalization Peer-reviewed

    N. Abe, D. Oka, K. Kaminaga, D. Shiga, D. Saito, T. Yamamoto, N. Kimura, H. Kumigashira, T. Fukumura

    Phys. Rev. B　106　125106　2022/09/06

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.106.125106 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  22. Surface proton conduction below 100°C of Ce0.80Sm0.20O2-δ thin film with oxygen vacancies Peer-reviewed

    G. Notake, D. Nishioka, H. Murasawa, M. Takayanagi, Y. Fukushima, H. Ito, T. Takada, D. Shiga, M. Kitamura, H. Kumigashira, T. Higuchi

    Jpn. J. Appl. Phys.　61　SD1017　2022/04/20

    Publisher: IOP Publishing

    DOI： 10.35848/1347-4065/ac4feb 　

    ISSN： 0021-4922

    eISSN： 1347-4065

  23. Rocksalt-type PrO epitaxial thin film as a weak ferromagnetic Kondo lattice Peer-reviewed

    H. Shimizu, D. Oka, K. Kaminaga, D. Saito, T. Yamamoto, N. Abe, N. Kimura, D. Shiga, H. Kumigashira, T. Fukumura

    Phys. Rev. B　105　014442　2022/01/31

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.105.014442 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  24. Room-Temperature Preparation of Ta Ions-Containing Ionic Liquid and its Vapor Deposition toward Ta-Oxide Film Coating Peer-reviewed

    N. Hozuki, K. Kaminaga, S. Maruyama, D. Shiga, H. Kumigashira, H. Takato, M. Kondo, Y. Matsumoto

    J. Electrochem. Soc.　169　013504　2022/01/27

    Publisher: The Electrochemical Society

    DOI： 10.1149/1945-7111/ac48c5 　

    ISSN： 0013-4651

    eISSN： 1945-7111

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    <title>Abstract</title> Ta ions-containing solutions, which are brown in color with no precipitation, were successfully prepared through an electroelution process with ionic liquid (IL). An as-delivered Ta metal plate covered with a passivation oxide film could be easily eluted even at room temperature by simply applying an anodic potential of, e.g. +2.2 V vs. Ag in [Bmim][PF6] IL. According to the quantity of electric charge required for oxidation of Ta, most Ta ions in the IL were suggested to be in an oxidation state of +5, which was also confirmed by x-ray photoemission spectroscopy (XPS). Ta ions in IL were found to thermally evaporate together with IL molecules by heating in a vacuum, forming a deposit of the Ta ions-containing IL on a substrate. The Ta concentrations in the deposits were reduced uniquely by about one order of magnitude from those in the original bulk source through the evaporation process under the present conditions. Furthermore, a possibility of the formation of thin film-like Ta oxide from such a Ta ions-containing IL deposit and its bulk droplet prepared on substrates by annealing in air at 1000oC will be discussed.

  25. Surface Electron–Ion Mixed Conduction of BaTiO3−δ Thin Film with Oxygen Vacancies Peer-reviewed

    T. Takada, T. Fujita, T. Imagawa, E. Yamamoto, J. Kano, D. Shiga, K. Horiba, H. Kumigashira, T. Higuchi

    J. Phys. Soc. Jpn.　90　(1)　014707　2021/01/15

    Publisher: Physical Society of Japan

    DOI： 10.7566/jpsj.90.014707 　

    ISSN： 0031-9015

    eISSN： 1347-4073

  26. Molecular beam epitaxy growth of the highly conductive oxide SrMoO3 Peer-reviewed

    H. Takatsu, N. Yamashina, D. Shiga, R. Yukawa, K. Horiba, H. Kumigashira, T. Terashima, H. Kageyama

    J. Cryst. Growth　543　125685　2020/08

    Publisher: Elsevier BV

    DOI： 10.1016/j.jcrysgro.2020.125685 　

    ISSN： 0022-0248

  27. Insulator-to-Metal Transition of Cr2O3 Thin Films via Isovalent Ru3+ Substitution Peer-reviewed

    K. Fujiwara, M. Kitamura, D. Shiga, Y. Niwa, K. Horiba, T. Nojima, H. Ohta, H. Kumigashira, A. Tsukazaki

    Chem. Mater.　32　5272　2020/06/23

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.chemmater.0c01497 　

    ISSN： 0897-4756

    eISSN： 1520-5002

  28. Electronic structure of a (3×3)-ordered silicon layer on Al(111) Peer-reviewed

    Y. Sato, Y. Fukaya, M. Cameau, A. K. Kundu, D. Shiga, R. Yukawa, K. Horiba, C.-H. Chen, A. Huang, H.-T. Jeng, T. Ozaki, H. Kumigashira, M. Niibe, I. Matsuda

    Phys. Rev. Mater.　4　(6)　064005　2020/06/15

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevmaterials.4.064005 　

    eISSN： 2475-9953

  29. Relationship between charge redistribution and ferromagnetism at the heterointerface between the perovskite oxides LaNiO3 and LaMnO3 Peer-reviewed

    M. Kitamura, M. Kobayashi, E. Sakai, M. Minohara, R. Yukawa, D. Shiga, K. Amemiya, Y. Nonaka, G. Shibata, A. Fujimori, H. Fujioka, K. Horiba, H. Kumigashira

    Phys. Rev. B　100　245132　2019/12/19

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.100.245132 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  30. Control of two-dimensional electronic states at anatase TiO2(001) surface by K adsorption Peer-reviewed

    R. Yukawa, M. Minohara, D. Shiga, M. Kitamura, T. Mitsuhashi, M. Kobayashi, K. Horiba, H. Kumigashira

    Phys. Rev. B　97　165428　2018/04/23

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.97.165428 　

    ISSN： 2469-9950

    eISSN： 2469-9969

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Misc. 9

  1. 放射光電子分光を用いた強相関透明素子の電子状態に関する研究

    神田龍彦, 志賀大亮, 湯川龍, 北村未歩, 堀場弘司, 吉松公平, 組頭広志

    PF News　42　(3)　21　2024/11

  2. Thickness Dependence of Electronic and Crystal Structures in VO2 Ultrathin Films

    D. Shiga, B. E. Yang, N. Hasegawa, T. Kanda, R. Tokunaga, K. Yoshimatsu, R. Yukawa, M. Kitamura, K. Horiba, H. Kumigashira

    PF Highlights '20　16　2021/11

  3. バナジウム酸化物デバイス界面に出現する新たな電子相に関する研究

    志賀大亮, 簔原誠人, 吉松公平, 湯川龍, 北村未歩, 堀場弘司, 組頭広志

    PF News　39　(2)　20　2021/08

  4. VO2極薄膜における電子・結晶構造の膜厚依存性

    志賀大亮, 楊以理, 長谷川直人, 神田龍彦, 德永凌祐, 吉松公平, 湯川龍, 北村未歩, 堀場弘司, 組頭広志

    放射光　34　(2)　86　2021/03

  5. Emergence of metallic monoclinic states in electron-doped VO2 films

    D. Shiga, H. Kumigashira

    '2019 at KEK: Annual Report'　58　2020/12

  6. Emergence of Metallic Monoclinic States of Electron-Doped VO2 Films

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, K. Horiba, H. Kumigashira

    PF Highlights '18　18　2019/10

  7. K蒸着によるVO2薄膜の金属–絶縁体転移制御: III. 単斜晶系金属相の出現

    志賀大亮, 簔原誠人, 北村未歩, 湯川龍, 堀場弘司, 組頭広志

    Photon Factory Activity Report　36　36　2019/04

  8. K蒸着によるVO2薄膜の金属–絶縁体転移制御II

    志賀大亮, 簔原誠人, 北村未歩, 湯川龍, 堀場弘司, 組頭広志

    Photon Factory Activity Report　35　65　2018/05

  9. K蒸着によるVO2薄膜の金属絶縁体転移制御

    志賀大亮, 簔原誠人, 北村未歩, 湯川龍, 三橋太一, 堀場弘司, 組頭広志

    Photon Factory Activity Report　34　86　2017/06

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Presentations 36

  1. Layer-Selective Observation of Collective Phase Transition in VO2-Based Heterostructures by in situ Photoemission Spectroscopy (to be presented in Dec. 2025) International-presentation

    D. Shiga, S. Inoue, T. Kanda, N. Hasegawa, M. Kitamura, K. Horiba, K. Yoshimatsu, A. F. Santander-Syro, H. Kumigashira

    Materials Research Meeting '25　2025/12/11

  2. 光電子分光によるバナジウム酸化物二層構造の電子相転移に関する研究 Invited

    志賀大亮

    ナノテラスARPES若手シンポジウム　2025/03/21

  3. 放射光光電子光による(CrxV1−x)2O3エピタキシャル薄膜の電子状態

    志賀大亮, 西翔平, 井上晴太郎, T. Tirasutt, 早坂亮太朗, 渡邉颯彦, 小澤健一, 吉松公平, 組頭広志

    第38回日本放射光学会年会・放射光科学合同シンポジウム　2025/01/11

  4. Photoemission Study on VO2-Based Bilayer Structures Invited

    D. Shiga

    Joint Meeting of the Tohoku Area Chemistry Societies　2024/09/14

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    会議名: 令和６年度化学系学協会東北大会 主催: 日本化学会東北支部 共催: 日本分光学会東北支部 依頼講演@コロキウム（物理化学） 講演番号: 14G2

  5. Photoemission Study on VO2/V1−xWxO2 Bilayer Structures International-presentation

    D. Shiga, S. Inoue, T. Kanda, N. Hasegawa, M. Kitamura, K. Horiba, K. Yoshimatsu, H. Kumigashira

    The 10th International Symposium on Functional Materials　2024/08/03

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    P1-12

  6. Electronic Structure of Hole-Doped CrxV1−xO2 Epitaxial Films Studied by in situ Photoemission Spectroscopy International-presentation

    D. Shiga, X. Cheng, T. T. Kim, T. Kanda, N. Hasegawa, M. Kitamura, K. Yoshimatsu, H. Kumigashira

    The International Conference on the Science and Technology for Advanced Ceramics and Data Driven Materials Research for Electronics　2024/02/29

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    The International Conference on the Science and Technology for Advanced Ceramics (STAC) - Data Driven Materials Research for Electronics (D2MatE)

  7. Electronic Phase Diagram of Cr-Doped VO2 Epitaxial Films Studied by in situ Photoemission Spectroscopy

    D. Shiga, X. Cheng, T. T. Kim, T. Kanda, N. Hasegawa, M. Kitamura, K. Yoshimatsu, H. Kumigashira

    2023/03/15

  8. VO2極薄膜における電子・結晶構造の膜厚依存性: 協調的モット-パイエルス転移の抑制 Invited

    志賀大亮, 楊以理, 長谷川直人, 神田龍彦, 德永凌祐, 吉松公平, 湯川龍, 北村未歩, 堀場弘司, 組頭広志

    第69回応用物理学会春季学術講演会　2022/03/23

  9. 放射光光電子光による(CrxV1−x)2O3エピタキシャル薄膜の電子状態

    志賀大亮, 西翔平, 井上晴太郎, T. Tirasutt, 早坂亮太朗, 渡邉颯彦, 小澤健一, 吉松公平, 組頭広志

    2024年度量子ビームサイエンスフェスタ　2025/03/13

  10. Electronic Structure of Hole-Doped CrxV1−xO2 Epitaxial Films Studied by in situ Photoemission Spectroscopy International-presentation

    D. Shiga, X. Cheng, T. T. Kim, T. Kanda, N. Hasegawa, M. Kitamura, K. Yoshimatsu, H. Kumigashira

    The 7th Symposium for The Core Research Clusters for Materials Science and Spintronics　2023/11/28

  11. Electronic Structure of Hole-Doped CrxV1−xO2 Epitaxial Films Studied by in situ Photoemission Spectroscopy International-presentation

    D. Shiga, X. Cheng, T. T. Kim, T. Kanda, N. Hasegawa, M. Kitamura, K. Yoshimatsu, H. Kumigashira

    29th International Workshop on Oxide Electronics　2023/10/16

  12. Photoemission Study of Electronic Structures in Epitaxial CrxV1−xO2 Films

    D. Shiga, X. Cheng, T. T. Kim, T. Kanda, N. Hasegawa, M. Kitamura, K. Yoshimatsu, H. Kumigashira

    2022/09/21

  13. Thickness Dependence of Electronic and Crystal Structures in VO2 Ultrathin Films

    D. Shiga, B. E. Yang, N. Hasegawa, T. Kanda, R. Tokunaga, K. Yoshimatsu, R. Yukawa, M. Kitamura, K. Horiba, H. Kumigashira

    Materials Research Meeting '21　2021/12/15

  14. Novel electronic phase emerging at VO2 device interface Invited

    Daisuke SHIGA

    4th Jt. Symp. Taipei Tech–Tohoku Univ.　2021/11/30

  15. VO2/W:VO2ヘテロ構造における電子相転移の直接観測

    志賀大亮, 神田龍彦, 長谷川直人, 北村未歩, 堀場弘司, 吉松公平, 組頭広志

    第82回応用物理学会秋季学術講演会　2021/09/12

  16. バナジウム酸化物デバイス界面に出現する新たな電子相の解明と制御

    志賀大亮, 楊以理, 長谷川直人, 神田龍彦, 德永凌祐, 吉松公平, 湯川龍, 北村未歩, 堀場弘司, 組頭広志

    2020年度量子ビームサイエンスフェスタ　2021/03/10

  17. VO2極薄膜における電子・結晶構造の膜厚依存性

    志賀大亮, 楊以理, 長谷川直人, 神田龍彦, 德永凌祐, 吉松公平, 湯川龍, 北村未歩, 堀場弘司, 組頭広志

    第34回日本放射光学会・放射光科学合同シンポジウム　2021/01/09

  18. Thickness dependence of electronic and crystal structures in VO2 ultrathin films

    D. Shiga

    3rd Jt. Symp. Taipei Tech–Tohoku Univ.　2020/11/30

  19. Thickness dependence of electronic and crystal structures in VO2 ultrathin films

    D. Shiga

    7th KEK Student Day　2020/11/17

  20. VO2極薄膜における電子・結晶構造の膜厚依存性

    志賀大亮, 楊以理, 長谷川直人, 神田龍彦, 德永凌祐, 吉松公平, 湯川龍, 北村未歩, 堀場弘司, 組頭広志

    第81回応用物理学会秋季学術講演会　2020/09/08

  21. VO2極薄膜における電子・結晶構造の膜厚依存性 Invited

    志賀大亮

    第9回酸化物研究の新機軸に向けた学際討論会　2020/08/07

  22. バナジウム酸化物デバイス界面に出現する新たな電子相の解明と制御

    志賀大亮, 楊以理, 長谷川直人, 神田龍彦, 德永凌祐, 北村未歩, 湯川龍, 吉松公平, 堀場弘司, 組頭広志

    2019年度量子ビームサイエンスフェスタ　2020/03/14

  23. VO2/TiO2(001)極薄膜における電子状態の膜厚依存性

    志賀大亮, 楊以理, 長谷川直人, 神田龍彦, 德永凌祐, 北村未歩, 湯川龍, 吉松公平, 堀場弘司, 組頭広志

    第67回応用物理学会春季学術講演会　2020/02/28

  24. Emergence of Metallic Monoclinic States of Electron-Doped VO2 Films

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, K. Horiba, H. Kumigashira

    The 3rd Symposium for The Core Research Clusters for Materials Science and Spintronics　2020/02/10

  25. Emergence of Metallic Monoclinic States of VO2 Films Induced by K Deposition

    D. SHiga, M. Minohara, M. Kitamura, R. Yukawa, K. Horiba, H. Kumigashira

    6th KEK Student Day　2019/11/12

  26. Emergence of Metallic Monoclinic States of VO2 Films Induced by K Deposition

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, K. Horiba, H. Kumigashira

    26th International Workshop on Oxide Electronics　2019/09/30

  27. Emergence of Metallic Monoclinic States of VO2 Films Induced by K Deposition

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, K. Horiba, H. Kumigashira

    The 40th International Conference on Vacuum Ultraviolet and X-ray Physics　2019/07/02

  28. K蒸着したVO2薄膜における単斜晶系金属相の出現

    志賀大亮, 簔原誠人, 北村未歩, 湯川龍, 堀場弘司, 組頭広志

    第66回応用物理学会春季学術講演会　2019/03/10

  29. Control of the Metal–Insulator Transition in VO2 Thin Films by K Deposition. II. Detailed Temperature Dependence

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, K. Horiba, H. Kumigashira

    5th KEK Student Day　2018/11/13

  30. Control of the Metal–Insulator Transition in VO2 Thin Films by K Deposition

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, K. Horiba, H. Kumigashira

    14th Int. Conf. Atom. Control. Surf. Interface and Nanostruct.　2018/10/23

  31. K蒸着によるVO2薄膜の金属–絶縁体転移制御

    志賀大亮, 簔原誠人, 北村未歩, 湯川龍, 三橋太一, 堀場弘司, 組頭広志

    第65回応用物理学会春季学術講演会　2018/03/20

  32. K蒸着によるVO2薄膜の金属–絶縁体転移制御

    志賀大亮, 簔原誠人, 北村未歩, 湯川龍, 三橋太一, 堀場弘司, 組頭広志

    2017年度量子ビームサイエンスフェスタ　2018/03/03

  33. K蒸着によるVO2薄膜の金属絶縁体転移制御

    志賀大亮, 簔原誠人, 北村未歩, 湯川龍, 三橋太一, 堀場弘司, 組頭広志

    第31回日本放射光学会・放射光科学合同シンポジウム　2018/01/10

  34. Control of the metal-insulator transition in VO2 thin films by K deposition

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, T. Mitsuhashi, K. Horiba, H. Kumigashira

    4th KEK Student Day　2017/10/24

  35. Control of the metal-insulator transition in VO2 thin films by K deposition

    D. Shiga, M. Minohara, M. Kitamura, R. Yukawa, T. Mitsuhashi, K. Horiba, H. Kumigashira

    24th International Workshop on Oxide Electronics　2017/09/26

  36. K蒸着によるVO2薄膜の金属絶縁体転移制御

    志賀大亮, 簔原誠人, 三橋太一, 北村未歩, 湯川龍, 堀場弘司, 組頭広志

    日本物理学会第72回年次大会　2017/03/19

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Research Projects 2

  1. 強相関酸化物界面設計に基づく電子・結晶構造相転移の独立制御

    志賀 大亮

    Offer Organization: (文科)

    System: 科研費

    Category: 【基金】若手研究

    Institution: 東北大

    2023/04 - 2026/03

  2. Elucidation of Collective Electronic Phase Transition Induced at Device Interfaces Based on Correlated Oxides Competitive

    Offer Organization: Japan Society for the Promotion of Science (JSPS)

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Research Activity Start-up

    Institution: Tohoku University

    2021/08 - 2024/03

Teaching Experience 4

  1. Basic Experiments in Chemistry　AMC Course, Tohoku Univ.

  2. Exercises in Physical Chemistry A　AMC Course, Tohoku Univ.

  3. Laboratory Experiments in Chemistry B　AMC Course, Tohoku Univ. Undergraduate (specialized)

  4. Exercises in Physical Chemistry B　AMC Course, Tohoku Univ. Undergraduate (specialized)

Social Activities 1

  1. 東北大学大学院理学研究科オンライン合同入試説明会2021

    2021/04/30 -

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    博士課程で身につく力ー博士進学のキャリア形成上の意義ー

Media Coverage 3

  1. 東北大と高エネ研、ナノ構造内における強相関電子の量子化条件の特定に成功

    日本経済新聞

    2023/05

    Type: Newspaper, magazine

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    エネルギーが連続的なアナログ値から離散的なデジタル値になる量子化は、現代のナノテクノロジーの基本となる現象です。近年、強い電子相関をもつ酸化物においても量子化現象が観測され、この現象を利用した新しい量子物質や量子デバイス創成が期待されています。しかしながら、酸化物中の強相関電子と呼ばれる強く相互作用した電子が量子化するための条件がわかっていませんでした。酸化物の類い希な機能を用いたモットトランジスタなどの設計において、このことが大きな障害となっていました。東北大学多元物質科学研究所の神田龍彦大学院生、志賀大亮助教、吉松公平准教授、組頭広志教授らの研究グループは、高エネルギー加速器研究機構物質構造科学研究所の北村未歩助教（現在は量子科学技術研究開発機構）と共同で、高輝度放射光を用いた角度分解光電子分光という手法を用いて、酸化物における量子化条件を決定することに成功しました。

  2. 東北大と高エネ研、共鳴トンネル効果を用いたモットトランジスタの原理検証に成功

    日本経済新聞

    2021/12

    Type: Newspaper, magazine

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    モットトランジスタは、高性能で消費電力の低いトランジスタが実現できることから、次世代デバイスの有力候補として盛んに研究されています。モットトランジスタでは、モット絶縁体における電気を流さない「電子固体」と電気を流す「電子液体」間の電子相転移（モット転移）を利用してOn/Offを切り替えます。しかし、モットトランジスタにおいては、従来広く用いられてきた電界効果型トランジスタ構造ではさまざまな原理的な問題がありました。東北大学多元物質科学研究所の組頭広志教授らの研究グループは、高エネルギー加速器研究機構物質構造科学研究所の湯川龍特任助教（現:大阪大学大学院工学研究科 助教）らと共同で、量子井戸間の共鳴トンネル効果を利用した新しい原理で動作するモットトランジスタを開発しました。

  3. 東北大と高エネ研、二酸化バナジウムのナノ構造において量子サイズ効果により新しい電子相が生じることを発見

    日本経済新聞

    2020/09

    Type: Newspaper, magazine

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    二酸化バナジウム（VO2）は室温付近で巨大な金属・絶縁体転移を示すことから、次世代デバイス材料として盛んに研究されている機能性酸化物の一つです。しかし、VO2の示す金属・絶縁体転移においては、デバイス設計に必須となるナノ領域における振る舞いはよく分かっていませんでした。東北大学多元物質科学研究所の志賀大亮大学院生、吉松公平講師、組頭広志教授らの研究グループは、高エネルギー加速器研究機構 物質構造科学研究所の北村未歩助教、堀場弘司准教授等と共同で、VO2をナノレベルまで薄くすると従来とは異なる新しい電子相が現れることを明らかにしました。